[CRIU] [PATCH v2] Add docker phaul driver

Hui Kang hkang.sunysb at gmail.com
Wed Oct 21 07:42:52 PDT 2015


On Wed, Oct 21, 2015 at 8:07 AM, Pavel Emelyanov <xemul at parallels.com> wrote:
> On 10/20/2015 07:53 PM, Hui Kang wrote:
>> Hi, Pavel,
>> I am able to remove more if htype.name() == "docker in the patch set 3
>>
>> https://lists.openvz.org/pipermail/criu/2015-October/022921.html
>>
>> Please see my inline reply. Another problem I met is that: after I
>> enable criu_conn to remove some "if htype.name() == "docker ", docker
>> migration and CPU validation suceeeds. However on the client side, I
>> got such error at end
>>
>> 16:17:39.250: Asking target host to restore
>> Error (cr-service.c:103): RPC error: Invalid req: Success
>> 16:17:41.555: CRIU RPC error (0/7)
>> Traceback (most recent call last):
>>   File "./p.haul", line 79, in <module>
>>     worker.start_migration()
>>   File "/root/development/p.haul/phaul/p_haul_iters.py", line 264, in
>> start_migration
>>     resp = self.criu_connection.ack_notify()
>>   File "/root/development/p.haul/phaul/criu_api.py", line 74, in ack_notify
>>     return self._recv_resp()
>>   File "/root/development/p.haul/phaul/criu_api.py", line 53, in _recv_resp
>>     raise Exception("CRIU RPC error (%d/%d)" % (resp.type, self._last_req))
>> Exception: CRIU RPC error (0/7)
>>
>> Could you help on this? Thanks.
>
> What's the gitid of the p.haul sources you use? I see no line 264
> in mine :) And -- what's in CRIU logs, it looks like some errors
> in notification handling.

This is becuase the p.haul I am uisng is patched with changes for
docker; so it has line 264.

I checked the log of criu daemon on source and destination. They are the same:

# cat /log
(00.000170) The service socket is bound to /var/run/criu_service.socket
(00.000740) Waiting for connection...

At first, I thought the log does not show any connection because the
docker driver will not make criu_req to the criu daemon. This may also
explain that why the notification handling fails.

However, later I realized that the validate_cpu makes request to the
criu daemon. So I do not understand why the criulog does not show any
connection. Can you explain this? Thanks.

- Hui

>
> -- Pavel
>
>> - Hui
>>
>>
>> On Tue, Oct 20, 2015 at 5:29 AM, Pavel Emelyanov <xemul at parallels.com> wrote:
>>> Hi, Hui, find my comments inline.
>>>
>>> Overall this is much better, but still I'd like to have even less
>>> "if htype.name() == "docker"" stubs over the code. Let's discuss (inline)
>>> what issues you're trying to solve and rework the generic p.haul code
>>> respectively.
>>>
>>>> index 11b3dbb..fd2baa3 100644
>>>> --- a/phaul/images.py
>>>> +++ b/phaul/images.py
>>>> @@ -140,6 +140,11 @@ class phaul_images:
>>>>               logging.info("Sending images to target")
>>>>
>>>>               start = time.time()
>>>> +
>>>> +             if htype.get_driver_name() == "docker" :
>>>> +                     htype.send_criu_images()
>>>> +                     return
>>>
>>> In docker driver the send_criu_images() anyway starts the fs_haul_subtree
>>> and rsync-s them. Can you teach the docker driver to always return the
>>> subtree fs hauler to avoid this "if"?
>>
>> In v3, I use send_criu_images for docker and sync_imgs_to_target() for
>> other types. I agreed that it would be better to merge them together.
>> So I list it as a todo task.
>>
>>>
>>>> +
>>>>               cdir = self.image_dir()
>>>>
>>>>               target_host.start_accept_images(phaul_images.IMGDIR)
>>>
>>>> diff --git a/phaul/p_haul_iters.py b/phaul/p_haul_iters.py
>>>> index b2c76e3..8f8fb73 100644
>>>> --- a/phaul/p_haul_iters.py
>>>> +++ b/phaul/p_haul_iters.py
>>>> @@ -36,6 +36,13 @@ class phaul_iter_worker:
>>>>               self.img = images.phaul_images("dmp")
>>>>
>>>>               self.htype = p_haul_type.get_src(p_type)
>>>> +
>>>> +             if self.htype.get_driver_name() != "docker" :
>>>> +                     # docker will talk to swrk in runc
>>>> +                     self.criu_connection = criu_api.criu_conn(self.data_socket)
>>>> +             else:
>>>> +                     self.criu_connection = ""
>>>> +
>>>
>>> You want to make the "dump" and "pre_dump" stages via Docker API too, am I right?
>>
>> Yes. I will do this seperately for runC and docker.
>>
>>>
>>>>               if not self.htype:
>>>>                       raise Exception("No htype driver found")
>>>>
>>>> @@ -55,13 +62,16 @@ class phaul_iter_worker:
>>>>
>>>>       def set_options(self, opts):
>>>>               self.target_host.set_options(opts)
>>>> -             self.criu_connection.verbose(opts["verbose"])
>>>> -             self.criu_connection.shell_job(opts["shell_job"])
>>>> +             if self.htype.get_driver_name() != "docker" :
>>>> +                     self.criu_connection.verbose(opts["verbose"])
>>>> +                     self.criu_connection.shell_job(opts["shell_job"])
>>>> +
>>>>               self.img.set_options(opts)
>>>>               self.htype.set_options(opts)
>>>>               self.fs.set_options(opts)
>>>>               self.__force = opts["force"]
>>>>               self.pre_dump = opts["pre_dump"]
>>>> +             self.target_host_ip = opts["to"]
>>>>
>>>>       def validate_cpu(self):
>>>>               logging.info("Checking CPU compatibility")
>>>> @@ -103,13 +113,39 @@ class phaul_iter_worker:
>>>>
>>>>               migration_stats.start()
>>>>
>>>> -             if not self.__force:
>>>> -                     self.validate_cpu()
>>>> +             # TODO fix it
>>>> +             if self.htype.get_driver_name() != "docker" :
>>>> +                     if not self.__force:
>>>> +                             self.validate_cpu()
>>>
>>> P.haul does CPU validation itself.
>>
>> Applied in v3.
>>
>>>
>>>>
>>>>               logging.info("Preliminary FS migration")
>>>>               self.fs.set_work_dir(self.img.work_dir())
>>>>               self.fs.start_migration()
>>>>
>>>> +             logging.info("Starting iterations")
>>>> +
>>>> +             # For Docker, we take a different path
>>>> +             if self.htype.get_driver_name() == "docker" :
>>>> +                     logging.info("Take a special path for Docker")
>>>> +
>>>> +                     self.htype.dump()
>>>> +                     logging.info("\tDocker dump succeeded")
>>>> +                     logging.info("FS and images sync")
>>>> +                     # sync the aufs filesystem again
>>>> +                     self.fs.stop_migration()
>>>> +
>>>> +                     # send the docker criu image to host
>>>> +                     self.htype.send_criu_images(self.target_host_ip)
>>>> +
>>>> +                     logging.info("Asking target host to restore")
>>>> +                     self.target_host.restore_from_images()
>>>> +
>>>> +                     return
>>>
>>> Would setting the self.pre_dump to "NO" help to avoid the hand-made
>>> code above?
>>
>> Applied in v3.
>>
>>>
>>>> +
>>>> +             # TODO: Do not do predump for docker right now. Add page-server
>>>> +             #       to docker C/R API, then we can enable
>>>> +             #        the pre-dump
>>>> +
>>>>               logging.info("Checking for Dirty Tracking")
>>>>               if self.pre_dump == PRE_DUMP_AUTO_DETECT:
>>>>                       # pre-dump auto-detection
>>>
>>>> diff --git a/phaul/p_haul_service.py b/phaul/p_haul_service.py
>>>> index 11883a6..f0667fc 100644
>>>> --- a/phaul/p_haul_service.py
>>>> +++ b/phaul/p_haul_service.py
>>>> @@ -45,17 +45,19 @@ class phaul_service:
>>>>               logging.info("Setting up service side %s", htype_id)
>>>>               self.img = images.phaul_images("rst")
>>>>
>>>> -             self.criu_connection = criu_api.criu_conn(self._mem_sk)
>>>>               self.htype = p_haul_type.get_dst(htype_id)
>>>>
>>>> -             # Create and start fs receiver if current p.haul module provide it
>>>> -             self.__fs_receiver = self.htype.get_fs_receiver(self._fs_sk)
>>>> -             if self.__fs_receiver:
>>>> -                     self.__fs_receiver.start()
>>>> +             if self.htype.get_driver_name() != "docker" :
>>>> +                     self.criu_connection = criu_api.criu_conn(self._mem_sk)
>>>> +                     # Create and start fs receiver if current p.haul module provide it
>>>> +                     self.__fs_receiver = self.htype.get_fs_receiver(self._fs_sk)
>>>> +                     if self.__fs_receiver:
>>>> +                             self.__fs_receiver.start()
>>>
>>> Make docker driver return empty receiver to avoid this "if".
>>
>> Applied in v3.
>>
>>>
>>>>
>>>>       def rpc_set_options(self, opts):
>>>> -             self.criu_connection.verbose(opts["verbose"])
>>>> -             self.criu_connection.shell_job(opts["shell_job"])
>>>> +             if self.htype.get_driver_name() != "docker" :
>>>> +                     self.criu_connection.verbose(opts["verbose"])
>>>> +                     self.criu_connection.shell_job(opts["shell_job"])
>>>>               self.img.set_options(opts)
>>>>               self.htype.set_options(opts)
>>>>
>>>
>>> -- Pavel
>>>
>> .
>>
>


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